The quality of waterfastness is of primary importance for today's ink jet media products. The term "waterfast" may be defined as the quality of being impervious to the effects of water. Products normally used out of doors, such as billboards, signs, etc., require protection from typical outdoor moisture sources such as rain, humidity, etc. Traditionally, non-waterfast ink jet film products have been laminated at high cost in order to enable outdoor usage. Ink jet office products also require waterfast properties to protect the printed image from typical indoor moisture sources such as humidity or the occasional spilled cup of coffee, etc.
Previous efforts to prepare waterfast ink jet film media involved mixing water-soluble polymer binders with water-soluble dye-fixing agents in an ink-receptive coating layer for an ink jet medium. While this approach can impart a certain amount of dye-fixing capability to the media, it does not give a substantially waterfast media. This is because most of the polymer binders and dye-fixing agents are water-soluble and do not give good wet adhesion to the base substrate. As a result, when contacted with water, these coatings swell and come off the substrates.
U.S. Pat. No. 5,439,739 discloses an ink jet recording medium comprising a support and at least one ink jet receiving layer, said ink receiving layer comprising a water-soluble polymer obtained by co-polymerizing 10-50 parts by weight of a quaternary salt monomer, 1-30 parts by weight of an amino group containing monomer or a carboxyl group containing monomer and 20-80 parts by weight of a monomer selected from acrylamide, methacrylamide, N,N-dimethacrylamide, N-isopropylacrylamide, diacetone acrylamide, N-methylolacrylamide, 2-hydroxyethyl-(meth)acrylate, and N-vinylpyrrolidone, and 0.1-30 parts by weight of a cross-linking agent.
U.S. Pat. Nos. 5,472,789 and 5,389,723 disclose a liquid-absorbent composition comprising a blend of (a) at least one polymeric matrix component comprising a cross-linkable polymer derived from .alpha., .beta.-ethylenically unsaturated monomers, (b) at least one polymeric liquid-absorbent component, (c) polyfunctional aziridine as a crosslinking agent, said composition capable of forming semi-interpenetrating networks wherein said at least one polymeric matrix component is crosslinked and said at least one liquid-absorbent component is uncrosslinked, said uncrosslinked liquid-absorbent component being able of being dissolved in the liquid that it is capable of absorbing.
U.S. Pat. No. 4,649,064 claims an ink-receiving layer containing (a) a hydrophilic cross-linkable film-forming material which is crosslinked to a degree sufficient to render it waterfast, while permitting it to rapidly absorb a water-based ink, (b) a crosslinking agent that is capable of crosslinking a cross-linkable colorant/resin composition in a water-based liquid ink.
WO 96/18496 discloses a water resistant ink jet receiving medium comprising an ink receptive layer of a crosslinked vinyl amide acrylic acid or methacrylic acid or ester thereof random copolymer and a cationic resin.
U.S. Pat. No. 5,532,064 discloses an ink-absorption layer having crosslinked gelatin in admixture with an amide in low concentration, generally less than approximately 1% or 2% by weight.
U.S. Pat. No. 4,701,837 discloses an ink-receiving layer mainly containing a water-soluble polymer and a crosslinking agent.
U.S. Pat. No. 5,206,071, entitled "Archivable Ink Jet Recording Media," discloses film media that are useful in ink jet printing, and which comprise a transparent, translucent or opaque substrate, having on at least one side thereof a water-insoluble, water-absorptive and ink-receptive matrix, said matrix comprised of a hydrogel complex and a polymeric high molecular weight quaternary ammonium salt.
U.S. Pat. No. 5,474,843 and WO 95/16561 disclose an ink-accepting coating layer containing (a) a water-soluble mordant that forms an insoluble compound with, and immobilizes the dyestuffs of, the ink jet inks, (b) a water-absorbing solid polymer, wherein said polymer has been rendered insoluble in water at room temperature by chemical hardening of said polymer at elevated temperature in an aqueous coating solution prior to coating of said coating solution, and (c) non-porous polymer beads dispersed in said water-absorbing polymer in an uppermost layer of said ink-accepting composition.